21.5 Million People Affected In Largest U.S. Government Hack In History

At left, Office of Personnel Management (OPM) Director Katherine Archuleta.

Susan Walsh / AP

Personal information of about 21.5 million current and former federal employees, as well as job applicants and contractors, was stolen when hackers infiltrated the government’s database for background checks, officials said Thursday.

The Office of Personnel Management (OPM) said that 19.7 million people who applied for a background check and 1.8 million non-applicants — mostly spouses or co-habitants — were affected in what is the largest data breach in U.S. government history.

The agency said it was “highly likely” that someone who had a background investigation through their offices as far back as 2000 was affected. People who applied before 2000 were “less likely" to have been affected.

Officials have attributed the cyber attack to Chinese hackers.

The latest finding is much higher than the 4.2 million figure OPM officials had previously stated. The breach was a result of two separate but related hacking incidents, OPM said.

According to the OPM, some of the breached records include interviews conducted by background investigators, Social Security Numbers, and about 1.1 million fingerprints. Health, criminal and financial history information were also compromised in the cyber attack.

The agency doesn’t believe the information has been misused or further disseminated.

In light of the cyber attacks, which were revealed in June, lawmakers have criticized the agency’s information technology vulnerabilities and are calling for the resignation of the OPM's director, Katherine Archuleta.

In its statement Thursday, the OPM said it would “take aggressive action” to strengthen its cyber security, including "two-factor" authentication for all system users, expanded monitoring, and hiring a new cyber security advisor.